You're not thick. The plan is to have a wiki repair manual for every device that gets better over time. For this iMac, we have parts, questions / answers, a description page about the device, but no step-by-step guides yet.
It will always be the case that we have a varying amount of information depending on the device. We're trying to make clear exactly what we have (and what we still need!) with the sidebar beneath the photo of the device. Suggestions are always welcome on communicating this better.
If anyone is interested in writing step-by-step guides for repairing the 24" iMac, go right ahead!